System and method for adjusting monitoring of timeslots during data transmission

ABSTRACT

A method for coordinating communications between a user equipment and a base station is presented. The method includes receiving an assignment of a first set of timeslots for at least one of uplink and downlink communications between the user equipment and the base station. The method also includes transmitting to the base station an instruction to delay a reduction of a number of timeslots monitored by the user equipment to less than the first set of timeslots for communications. In some implementations, the instruction comprises at least one of a predetermined communication and a block including at least one of a dummy block format and a specified block format. The method may include transmitting a control block to the base station, the control block identifying one or more timeslots being monitored by the user equipment

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and incorporates by reference U.S.Provisional Patent Application No. 61/171,425 which has the same titleand was filed on Apr. 21, 2009.

BACKGROUND

The present disclosure relates generally to data transmission protocolsin mobile communication systems and, more specifically, to systems andmethods for reduced timeslot monitoring during data transmission.

As used herein, the terms “mobile station” (MS), “user agent,” and “userequipment” (UE) can refer to electronic devices such as mobiletelephones, personal digital assistants, handheld or laptop computers,and similar devices that have network communications capabilities. Insome configurations, UE may refer to a mobile, wireless device. Such UEsthat are mobile, wireless devices may or may not include a subscriberidentity module (SIM) card. The terms may also refer to devices thathave similar capabilities but that are not readily transportable, suchas desktop computers, set-top boxes, or network nodes.

A UE may operate in a wireless communication network that provides forhigh-speed data communications. For example, the UE may operate inaccordance with Global System for Mobile Communications (GSM) andGeneral Packet Radio Service (GPRS) technologies. Today, such a UE mayfurther operate in accordance with Enhanced Data rates for GSM Evolution(EDGE), or Enhanced GPRS (EGPRS) or Enhanced GPRS Phase 2 (EGPRS2).

EDGE/EGPRS/EGPRS2 are examples of digital mobile communicationstechnology that allows for increased data transmission rate and improveddata transmission reliability. It is often classified as a 2.75G networktechnology. EDGE has been introduced into GSM networks around the worldsince approximately 2003, initially in North America. EDGE/EGPRS/EGPRS2may be used in any packet-switched application, such as those involvingan internet connection. High-speed data applications, such as video andother multimedia services, benefit from EGPRS' increased data capacity.

A UE operating in accordance with EGPRS/EGPRS2 may have multi-slotcapability that enables them to use between one (1) and eight (8) timeslots for data transfer. More timeslots may be used if a downlink dualcarrier configuration is supported. Since uplink and downlink channelsare reserved separately, various multi-slot resource configurations maybe assigned in different directions. UEs may be categorized into twotypes based on the multi-slot class that it supports. For example, (1)Multi-slot Classes 1-12, 19-45 (Type 1) UEs have multi-slot capabilityin the uplink (UL) and downlink (DL) directions and may use thiscapability quasi-simultaneously (for example, by transmitting orreceiving within the same time division multiple access (TDMA) frame).This group of multi-slot classes may use half duplex communication. Thereason for this limitation may be explained by selecting, for example,multi-slot class 26. In this case, the maximum allowable number oftimeslots in the UL is 4 and in the DL it is 8. Simultaneoustransmission and reception of this number of timeslots is possible onlyif the UE is capable of transmitting and receiving at the same time.This particular group, however, does not have such capability and thespecification limits their operation to half-duplex. However, (2)Multi-slot Class 13-18 (Type 2) UEs are the most advanced group of UEand have the capability to simultaneously transmit and receive (fullduplex communication), requiring splitters, duplexers, and filters toseparate transmit and receive paths.

Regardless of the particular type of UE, during operation, the UE isassigned timeslots during which the UE can communicate with the basestation. An assignment contains a set of timeslots on one (or, fordownlink dual carrier, two) channel(s). In the case of an uplinkassignment this is the total set of timeslots that may be used by the UEfor uplink transmissions; in the case of a downlink assignment, this isthe total set of timeslots on which the network may send data to the UE.For any given radio block period, the network dynamically allocatesresources and determines on which downlink timeslots or uplink timeslotsthe UE may receive and/or transmit data. In basic transmission timeintervals (BTTI), a given radio block period includes 4 TDMA frames andeach TDMA frame includes 8 timeslots. The allocation algorithm isimplementation dependent, but may take account of the UE's multislotclass (the maximum number of timeslots on which it can transmit/receive,and the time required to switch from transmit to receive and viceversa), and will usually take account of the amount of data the basestation controller (BSC) expects the UE to receive/transmit.

Reduced transmission time intervals (RTTI) can be used and is amodification to the above structure where, instead of a radio blockbeing transmitted as four bursts with each block sent in a particulartimeslot over four TDMA frames, a radio block (containing essentiallythe same amount of information) is transmitted using two timeslots intwo TDMA frames. This reduces the transmission time for a block andreduces the overall latency of the system. Accordingly, a “reduced radioblock period” is 2 TDMA frames (approx. 10 ms) compared with a basicradio block period, which is 4 TDMA frames (approx. 20 ms).

Uplink allocations are signaled by the use of an uplink state flag(USF), which is a number between 0 and 7 (inclusive), and is signaled inevery downlink radio block. As part of its uplink assignment, the UE isinformed which USF(s) on which timeslot(s) indicate an uplink allocationfor that UE. USFs are generally included in the headers of downlinkblocks. In the case of RTTI, USFs may be coded across radio blocksacross four TDMA frames, for example in the same manner as downlink BTTIradio blocks are sent (“BTTI USF mode”) or (using two timeslots) acrosstwo TDMA frames (“RTTI USF mode”).

In some communication standards, there are “m” timeslots assigned forreception and “n” timeslots assigned for transmission. Thus, for amultislot class type 1 UE, there may be Min(m,n,2) reception andtransmission timeslots with the same timeslot number. For a multislotclass type 2 UE, there may be Min(m,n) reception and transmissiontimeslots with the same timeslot number. In the case of downlink dualcarrier configurations, if timeslots with the same timeslot number areassigned on both channels, in calculating the value of m they may becounted as one timeslot. As a result, where both downlink and uplinktimeslots are assigned, if assigned a single timeslot in one directionand one or more timeslots in the opposite direction, the timeslot numberof the first timeslot may be the same as one of the timeslot(s) in theopposite direction. Similarly, if assigned two or more uplink timeslotsand two or more downlink timeslots, at least two of the uplink anddownlink timeslots may have a common timeslot number. As a result, inuplink+downlink assignments, the timeslots that may be monitored forUSFs and downlink data blocks are largely co-incident. In thisimplementation, assignments and allocations are essentially under thecontrol of the network (for example, the BSC).

Depending upon the system, Extended Dynamic Allocation (EDA) may providea mechanism to allow multiple uplink blocks to be allocated to a UE bymeans of a single USF indication. When this protocol is utilized for atemporary block flow (TBF), if a UE detects a USF allocating it anuplink block, it is also implicitly allocated uplink blocks sent in thesame radio block period using all timeslots which are part of itsassignment and which are numbered higher than that on which the USF wasreceived.

During an ongoing packet data session in GPRS, a UE with an assigneddownlink TBF is required to monitor all downlink timeslots in itsassignment in case the network sends it data during those timeslots.Similarly, if a UE has an assigned uplink TBF, it is required to monitorall timeslots on which the uplink state flag (USF) could be sent todynamically allocate uplink resources. If a UE has both uplink anddownlink TBFs, the UE may monitor as many relevant downlink timeslots aspossible, taking into account any uplink transmissions. The constantmonitoring of assigned timeslots requires the expenditure of significantamounts of wasted energy in the case that either the network or the UEhas nothing to send. This is particularly so when neither the networknor the UE has data to send. Although it is possible to release theassigned resources, this may lead to a user-perceived delay when furtherdata is to be sent, since the resources may be re-established.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of this disclosure, reference is nowmade to the following brief description, taken in connection with theaccompanying drawings and detailed description, wherein like referencenumerals represent like parts.

FIG. 1 is a block diagram of an exemplary communication system whichincludes user equipment (UE) such as a wireless or mobile communicationdevice which communicates through a wireless communication network witha base station (BS);

FIG. 2 is a flow chart setting forth the steps of an example method forreducing the number of timeslots monitored during data transmissionbetween UE and a BS;

FIG. 3 illustrates an example for defining a trigger through the absenceof a downlink transfer and an uplink transfer for a period of 1 second,or a period in which 5 consecutive USFs are unused and no downlinktransfer occurs, whichever happens earlier;

FIG. 4 illustrates an example for defining a trigger through 1consecutive second of no data transfer;

FIG. 5 illustrates an example for using a trigger that applies todownlink dual carrier data transmissions wherein, after detecting thetrigger, the timeslot reduction procedure applies independently on thetwo channels and where uplink and downlink timeslot reduction algorithmsoperate independently;

FIG. 6 illustrates an example of using a trigger using downlink dualcarrier assignment;

FIG. 7 illustrates an example of using a timeslot reduction algorithm,wherein the timeslots to be monitored for uplink state flags (USFs) arereduced as a result of multiple unused USFs;

FIG. 8 illustrates another example of using a timeslot reductionalgorithm, wherein a trigger is used for the reduction of both USF anddownlink monitoring;

FIG. 9 illustrates an example of using a timeslot reduction algorithmwith a downlink dual carrier assignment, wherein the trigger algorithmand any ongoing reduction in monitored timeslots continues after anassignment message is received;

FIG. 10 illustrates an example of using a timeslot reduction algorithmwith an extended dynamic allocation (EDA) protocol when a reduced set oftimeslots is being monitored;

FIG. 11 illustrates another example of using a timeslot reductionalgorithm with an extended dynamic allocation (EDA) protocol when areduced set of timeslots is being monitored and the timeslots beingmonitored vary over time;

FIG. 12 illustrates an example of using a timeslot reduction algorithmwith a reduced transmission time interval (RTTI) in the downlink and/orwhere RTTI USF mode is used to allocate uplink resources;

FIG. 13 is a sequence diagram illustrating an implementation of thepresent disclosure having a single trigger, wherein the trigger rulesvary between a network and a UE;

FIG. 14 is a sequence diagram illustrating an implementation of thepresent disclosure showing that the timeslots that the network believesthe UE to be monitoring are a subset of those that the UE is actuallymonitoring; and

FIG. 15 is a sequence diagram illustrating an implementation of thepresent disclosure with an RTTI assignment.

DETAILED DESCRIPTION

The present disclosure provides a system and method for reducingtimeslots for monitoring during data transmission.

The method may include identifying timeslots for uplink and downlinkcommunications between the user equipment and the base station,monitoring a predetermined number of timeslots for communications,tracking usage of at least a portion of the timeslots identified for atleast one of uplink communications and downlink communications, and uponreaching a predetermined usage metric related to at least one of uplinkcommunications and downlink communications, and triggering an automaticreduction in a number of timeslots monitored by the user equipment toless than the predetermined number of timeslots.

In one implementation, the present system includes a UE for use with acommunications network including a base station. The UE comprises aprocessor configured to receive a timeslot assignment from the basestation for uplink and/or downlink communications with the base station,monitor a predetermined number of timeslots assigned for communicationsbased on the timeslot assignment received from the base station, trackusage of at least a portion of the timeslots assigned for one of uplinkand downlink communications and upon usage of at least a portion of thetimeslots assigned for one of uplink and downlink communicationsreaching a threshold, trigger a unilateral adjustment of a number oftimeslots monitored to less than the predetermined number of timeslots.

In another implementation, the present system includes a base stationconfigured to communicate via a communications network for communicatingwith a UE. The base station includes a processor. The processor isconfigured to determine timeslots for uplink and downlink communicationswith the user equipment. The user equipment is configured to monitor thetimeslots. The processor is configured to track usage of at least aportion of the timeslots for uplink and downlink communications, andupon usage of at least a portion of the timeslots for uplink anddownlink communications reaching a first threshold, trigger a reductionin the number of timeslots allocated for uplink and downlinkcommunications.

The various aspects of the disclosure are now described with referenceto the annexed drawings, wherein like numerals refer to like orcorresponding elements throughout. It should be understood, however,that the drawings and detailed description relating thereto are notintended to limit the claimed subject matter to the particular formdisclosed. Rather, the intention is to cover all modifications,equivalents, and alternatives falling within the spirit and scope of theclaimed subject matter.

As used herein, the terms “component,” “system,” and the like areintended to refer to a computer-related entity, either hardware, acombination of hardware and software, software, or software inexecution. For example, a component may be, but is not limited to being,a process running on a processor, a processor, an object, an executable,a thread of execution, a program, and/or a computer. By way ofillustration, both an application running on a computer and the computercan be a component. One or more components may reside within a processand/or thread of execution and a component may be localized on onecomputer and/or distributed between two or more computers.

The word “exemplary” is used herein to mean serving as an example,instance, or illustration. Any aspect or design described herein as“exemplary” is not necessarily to be construed as preferred oradvantageous over other aspects or designs.

Furthermore, the disclosed subject matter may be implemented as asystem, method, apparatus, or article of manufacture using standardprogramming and/or engineering techniques to produce software, firmware,hardware, or any combination thereof to control a computer or processorbased device to implement aspects detailed herein. The term “article ofmanufacture” (or alternatively, “computer program product”) as usedherein is intended to encompass a computer program accessible from anycomputer-readable device, channel, or media. For example, computerreadable media can include but are not limited to magnetic storagedevices (for example, hard disk, floppy disk, magnetic strips, and thelike), optical disks (for example, compact disk (CD), digital versatiledisk (DVD), and the like), smart cards, and flash memory devices (forexample, card, stick, and the like). Additionally, it should beappreciated that a carrier wave can be employed to carrycomputer-readable electronic data such as those used in transmitting andreceiving electronic mail or in accessing a network such as the Internetor a local area network (LAN). Of course, those skilled in the art willrecognize many modifications may be made to this configuration withoutdeparting from the scope or spirit of the claimed subject matter.

Referring now to FIG. 1, a block diagram of an exemplary communicationsystem 100 includes a UE 102 (one example of a wireless or mobilecommunication device) that communicates through a wireless communicationnetwork 104. Depending upon system requirements, the present system 100may be used within other communication systems having differentimplementations. The UE 102 may include a visual display 112, a keyboard114, and perhaps one or more auxiliary user interfaces (UI) 116, each ofwhich are coupled to a processor or controller 106. The processor 106 iscoupled to a memory 107, radio frequency (RF) transceiver circuitry 108,and an antenna 110. Typically, the processor 106 is embodied as acentral processing unit (CPU) that runs operating system software in amemory component (not shown). The processor 106 will normally controloverall operation of UE 102, whereas signal processing operationsassociated with communication functions are typically performed in RFtransceiver circuitry 108. The processor 106 interfaces with the devicedisplay 112 to display received information, stored information accessedfrom the memory 107, user inputs, and the like. The keyboard 114, whichmay be a telephone type keypad or full or partial alphanumeric keyboard(physical or virtual), is normally provided for entering data forstorage in the UE 102, information for transmission to the network 104,a telephone number to place a telephone call, commands to be executed onthe UE 102, and a variety of other or different user inputs.

The UE 102 sends communication signals to and receives communicationsignals from the network 104 over a wireless link via the antenna 110.The RF transceiver circuitry 108 performs functions similar to those ofa tower station 118 (for example, a base transceiver station (BTS)) anda base station (BS) or base station controller (BSC) 120, including forexample modulation/demodulation and, possibly, encoding/decoding andencryption/decryption. To this end, the BS 120 may include, for example,a processor 121 and memory 122. It is also contemplated that the RFtransceiver circuitry 108 may perform certain functions in addition tothose performed by the BS 120. It will be apparent to those skilled inart that the RF transceiver circuitry 108 will be adapted to particularwireless network or networks in which the UE 102 is intended to operate.

The UE 102 includes a battery interface 134 for receiving one or morerechargeable batteries 138. The battery 138 supplies electrical power toelectrical circuitry in the UE 102, and the battery interface 134provides for a mechanical and electrical connection for the battery 132.The battery interface 134 is coupled to a regulator 136 that regulatespower to the UE 102. The UE 102 may be a handheld portable communicationdevice, which includes a housing that carries and contains theelectrical components of the UE 102 including the battery 138. The UE102 may operate using a subscriber identity module (SIM) 140 that isconnected to or inserted in the UE 102 at a SIM interface 142. The SIM140 is one type of a conventional “smart card” used to identify an enduser or subscriber of the UE 102 and to personalize the device, amongother things. To identify the subscriber, the SIM 140 may contain userparameters such as an international mobile subscriber identity (IMSI).The SIM 140 may store additional user information for the UE as well,including datebook or calendar information and recent call information.

The UE 102 may be a single unit, such as a data communication device, acellular telephone, a multiple-function communication device with dataand voice communication capabilities, a personal digital assistant (PDA)enabled for wireless communication, or a computer incorporating aninternal modem. Alternatively, the UE 102 may be a multiple-module unitcomprising a plurality of separate components, including but in no waylimited to a computer or other device connected to a wireless modem. Inparticular, for example, in the UE block diagram of FIG. 1, the RFtransceiver circuitry 108 and antenna 110 may be implemented as a radiomodem unit that may be inserted into a port on a laptop computer. Inthis case, the laptop computer would include the display 112, thekeyboard 114, one or more auxiliary Uls 116, and the processor 106embodied as the computer's CPU. The computer or other equipment may notnormally be capable of wireless communication and may be adapted toconnect to and effectively assume control of the RF transceivercircuitry 108 and the antenna 110 of a single-unit device such as one ofthose described above.

The UE 102 communicates with and through the wireless communicationnetwork 104. The wireless communication network 104 may be a cellulartelecommunications network. The wireless network 104 may be configuredin accordance with the requirements of General Packet Radio Service(GPRS) and Global Systems for Mobile (GSM) technologies. Alternatively,UE 102 may further operate in accordance with Enhanced Data rates forGSM Evolution (EDGE) or Enhanced GPRS (EGPRS). In such an environment,the wireless network 104 includes the base station (BS) 120 with theassociated tower station 118 and also a Mobile Switching Center (MSC)123, a Home Location Register (HLR) 132, a Serving General Packet RadioService (GPRS) Support Node (SGSN) 126, and a Gateway GPRS Support Node(GGSN) 128. The MSC 123 is coupled to the BS 120 and to a landlinenetwork, such as a Public Switched Telephone Network (PSTN) 124. TheSGSN 126 is coupled to the BS 120 and to the GGSN 128, which is in turncoupled to a public or private data network 130 (such as the Internet).The HLR 132 is coupled to the MSC 123, SGSN 126, and GGSN 128.

The station 118 is a fixed transceiver station, and the station 118 andBS 120 may be referred to as transceiver equipment. The transceiverequipment provides wireless network coverage for a particular coveragearea commonly referred to as a “cell.” The transceiver equipmenttransmits communication signals to and receives communication signalsfrom UEs within its cell via station 118. The transceiver equipmentnormally performs such functions as modulation and possibly encodingand/or encryption of signals to be transmitted to the UE in accordancewith particular, usually predetermined, communication protocols andparameters, under control of its controller. The transceiver equipmentsimilarly demodulates and, possibly, decodes and decrypts, if necessary,any communication signals received from the UE 102 within its cell.Communication protocols and parameters may vary between differentnetworks. For example, one network may employ a different modulationscheme and operate at different frequencies than other networks.

For all UEs 102 registered with a network operator, permanent data (suchas the UE 102 user's profile) as well as temporary data (such as theUE's 102 current location) may be stored in the HLR 132. In case of avoice call to the UE 102, the HLR 132 may be queried to determine thecurrent location of the UE 102. A Visitor Location Register (VLR) of theMSC 123 is responsible for a group of location areas and stores the dataof those UEs that are currently in its area of responsibility. Thisincludes parts of the permanent UE data that have been transmitted fromthe HLR 132 to the VLR for faster access. However, the VLR of the MSC123 may also assign and store local data, such as temporaryidentifications. Optionally, the VLR of the MSC 123 can be enhanced formore efficient co-ordination of GPRS and non-GPRS services andfunctionality, for example, paging for circuit-switched calls which canbe performed more efficiently via the SGSN 126, and combined GPRS andnon-GPRS location updates.

The SGSN 126 may be located at the same hierarchical level as that MSC123 and keeps track of the individual locations of UEs. The SGSN 126also performs security functions and access control. The GGSN 128provides interworking with external packet-switched networks and isconnected with SGSNs (such as the SGSN 126) via an IP-based GPRSbackbone network. The SGSN 126 performs authentication and ciphersetting procedures based on algorithms, keys, and criteria (e.g. as inexisting GSM).

During ongoing, traditional, GPRS or EGPRS packet data communicationsbetween the UE 102 through the wireless communication network 104, whenthe UE 102 is assigned a downlink temporary block flow (TBF), the UE 102is required to monitor all downlink timeslots in its assignment in theevent that the network transmits data during those timeslots. Forsimplicity, communications to and from the UE 102 will be described asbeing with the network 104, rather than a particular entity of thenetwork 104, such as the BS 102. However, one of skill in the art willreadily appreciate that such communications are often between the UE 102and the BS 120, or other entity. If the UE 102 has an assigned uplinkTBF, it is required to monitor all timeslots on which the uplink stateflag (USF) could be sent to dynamically allocate uplink resources. Ifthe UE 102 has both uplink and downlink TBFs, the UE 102 monitors asmany relevant downlink timeslots as possible, taking into account anyuplink transmissions. Thus, in traditional communications protocolsutilized with the system 100 of FIG. 1, a very structured communicationsprotocol is utilized whereby the UE 102 and BS 120 cooperate accordingto a coordinated DL, UL, and monitoring algorithm that permits the BS120 to control the allocation of resources.

However, the constant monitoring of assigned timeslots results in theexpenditure of significant depletion of the battery 138. This isparticularly undesirable in the case that either the network 104 or theUE 102 has nothing to send. Accordingly, in many circumstances, it isdifficult to determine whether it is more efficient to maintain anactive communication connection to improve performance, or to shutdownor minimize the connection to reduce energy use. For example, during webbrowsing, after the download of a page (whereby the last transmission ofRLC-layer data may correspond to the TCP-layer ACK sent by the UE 102),the UE 102 may immediately request further downloads without user input.This may occur when the UE 102, after downloading a web page,immediately proceeds to retrieve all embedded images within that page.Using the same application, however, the UE 102 may have received all ofthe information required to render the page, and may not send or receivedata via the network 104 for some time as the UE 102 waits for the userto request a new page or take some other action. In a file-transferprotocol (FTP) download, on completion of a download, the UE 102 mayeither initiate a subsequent transfer (e.g. if the user has requestedmultiple files and the ftp application limits the number of concurrentdownloads), or may stop to await user input. Similarly, in a dataupload, the last data to be sent may be from the network 104 to the UE102 (final acknowledgement); however, the BS 120 is agnostic to higherlayer protocols and applications, and cannot determine whether or notfurther data may be sent by the UE 102. In these examples, the network104, and in particular the BS 120, are not able to determine whetheradditional network communications will take place, or whether there willbe some delay due to waiting for user input.

As shown by these examples, difficulties may be associated withbidirectional assignments coordinated between the BS 120 and UE 102.Specifically, scenarios where human interaction is involved (such aspauses in data transmission corresponding to some ‘thinking/processingtime’ by the user), scenarios where the BS 120 is generally unable todetermine when a pause will start or how long a pause will last for, andscenarios where pauses generally result in simultaneous breaks in uplinkand downlink data transmission can all give rise to reduced battery lifeand/or slow response times for the user, depending on how the network isoperated.

For example, in some network implementations, the network 104 or BS 120attempts to determine or guess when no data will be sent by the UE 102and explicitly release the corresponding TBF resources (for example, seesub-clause 9.3.2.6 in 3GPP TS 44.060 v.8.3.0 “General Packet RadioService (GPRS); Mobile Station (MS)-Base Station System (BSS) interface;Radio Link Control/Medium Access Control (RLC/MAC) protocol (Release8)”). After releasing the corresponding TBF resource, when new data isto be sent, a TBF is re-established using existing procedures. Thisprocess, although allowing for the release of resources, does not allowfor the quick resumption of data transmissions. That is, this may leadto a user-perceived delay when further data is to be sent whileresources are re-established.

Alternatively, in some cases, it is possible to use an ‘extended uplinkTBF mode’ for the network 104 and, thereby, allow an uplink TBF tocontinue, even though the UE 102 has nothing to send. The BS 120 mayrequire the UE 102 to respond to all uplink allocations (for example,signaled by valid USFs) by sending dummy blocks when the UE 102 hasnothing else to send, or may allow the UE 102 to simply ignore USFs thatit has no use for. A similar approach is permitted for the downlink,where the network 104 can ensure that the TBF is maintained, even thoughthere is no data to send, by sending dummy blocks. When new data is tobe sent, it is sent using the existing resources. This process maintainsthe coordinated DL, UL, and monitoring algorithm utilized between the UE102 and BS 120 and control of the BS 120 over allocating resources.However, while allowing for quick resumption of data transmission, thisprocess is a substantial energy drain on the battery 138 of the UE 102because the UE 102 must continuously monitor the network 104communications and send dummy blocks to maintain access to datatransmission services.

In other attempts to address these issues, explicit signaling may bespecified by the network 104 to tell the UE 102 that it may monitor onlya subset of timeslots corresponding to its existing assignment. This isin effect a promise that when any subsequent downlink data is to besent, it will be sent using only the signaled subset of resources.Similarly, signaling may be used to indicate that any uplink allocationwill be signaled (by way of the assigned USF(s)) on a reduced set oftimeslots. Again, this method preserves the coordinated DL, UL, andmonitoring algorithm utilized between the UE 102 and BS 120 and controlof the BS 120 over allocating resources. This method, however, may beproblematic as the reduction is controlled by the BS 120 which haslittle, if any, knowledge of the application in use by the UE 102, andif or when any subsequent data transfer is likely to start. Also, theindependent control of uplink and downlink monitoring is complex, andthe dynamic signaling (every time the monitoring timeslots are reduced)is also complex. Finally, when non-persistent mode (NPM) is used in thismethod, the UE 102 may not receive the downlink block indicating thebitmap reduction and may consider this acceptable according to the rulesof NPM operation, which allows for blocks to be considered ‘abandoned’by the receiver if it has not successfully received the block after acertain length of time.

Turning now to FIG. 2, the steps 200 of a method for reducing a numberof timeslots for monitoring during data transmission between the UE 102and network 104 of FIG. 1 are provided. As will be described, themethods, algorithms, and protocols of the present disclosure break withthe traditional paradigm of rigidly coordinated DL and UL resourceassignments and strict explicit control by the BS 120 over assigningresources. Specifically, as will be described, by allowing the UE 102and the BS 120 to adjust the number of timeslots to be monitoredautomatically and independently, the UE 102 will use less energy tocommunicate with network 104/BS 120, while reducing the potential forresponsiveness lags that would be appreciable to the user of the UEs102. That is, the present disclosure provides a system and methodwhereby the UE 102 can adjust the number of timeslots to be monitoredand the BS 102 can reduce the number of timeslots which it expects theUE 102 to monitor automatically and irrespective of each other.

The process steps illustrated in FIG. 2 begin at process block 202 byassigning timeslots for uplink and downlink communications. According totraditional protocols described above, this assignment results in the UEand BS monitoring a predetermined number of the assigned timeslots, asindicated at process block 204. The usage of each monitored timeslot istracked at process block 206. The usage of each timeslot is thencompared to a usage metric at decision block 208. As will be described,this usage metric may act as a threshold value against which the trackedusage is compared. For example, the threshold indicated by the usagemetric may be a predetermined number of timeslots assigned for UL andunused by the UE. Other usage metrics may be based on the timeslots usedor unused by the BS or network. Thus, as will be described, this is butone example of a usage metric or threshold and many others may be used.Regardless of the specifics of the usage metric and particulars of howaction is triggered, if the tracked usage continues to exceed athreshold indicated by the usage metric, the predetermined number oftimeslots continues to be monitored.

However, if the tracked usage falls below a threshold indicated by theusage metric, the number of monitored timeslots may be reduced in step210. Thus, as will be described, this evaluation of the actual usagewith respect to the usage metrics acts as a trigger. These triggerscharacterize the communication activities between the UE 102 and network104/BS 120 and may identify a minimum threshold volume of traffic, atime period during which no transmission takes place, a number ofunder-utilized USFs, or any other characteristic of the communicationactivities between UE 102 and network 104. Upon determining that aparticular trigger has been satisfied, either UE 102 or network 104 mayunilaterally, or together, take action to minimize the number oftimeslots being monitored by the UE 102 and/or the number of timeslotsthat may be allocated to the UE 102 by the network 104.

To implement method 200, a number of triggers are defined. Each triggermay be based on the absence of data transmissions, or othercharacteristics of the communication activity between the UE 102 andnetwork 104. The triggers may be the same or different for the UE 102and network 104. Upon determining that a trigger event has occurred, thetimeslots to be monitored by the UE 102 are reduced or the timeslotsused by network 104 to send downlink data or USFs to the UE are reduced,or both. In one example, trigger parameters may be specified in acommunication standard, defined in assignment messages and/orestablished during packet data protocol (PDP) context establishmentprocedures, specified and/or signaled at TBF establishment ormodification, or any combination of these.

In one implementation, basic triggers are specified. The basic triggerdefinitions include parameters, for example, such as a time limit or anumber of non-responded-to USFs. The basic triggers may also becommunicated at TBF establishment or modification or, alternatively, atPDP context establishment, with the BSC being informed during PFCnegotiation for example.

A trigger may be designed to detect a lack of data transmissions by boththe network 104/BS 120 and UE 102 over a period of time. The trigger maybe specified using time measurement (e.g., a number of seconds), or apredetermined period of time during which a specified number of USFswhich allocate uplink resources to the UE are not used to send data. Alack of data in this context may be defined to include the sending ofdummy blocks such as a PACKET UPLINK DUMMY CONTROL BLOCK that contain nouser data.

Other trigger definitions may include a time period or number of radioblock periods in which no data has been sent by the UE 102 and/ornetwork 104/BS 120, a number of uplink allocated radio blocks that havenot been used to send data, a number of radio block periods during whichuplink resources were allocated but were not used to send data, or anycombination of the above. Referring now to FIG. 3, one example of atrigger can be defined by the absence of communication from the UE.FIGS. 3-12 are timing diagrams for use in illustrating the disclosedsystem and method for adjusting timeslot monitoring. The timing diagramswill be described with respect to the perspective of the UE. Thus, adownlink channel 300 and uplink channel 302 are shown. Referringparticularly to FIG. 3, a downlink data transfer 304 is shown thatrepresents data transferred from the BS to the UE. In addition, uplinkdata transfer 306 is shown that represents data transferred from the UEto the BS. However, following after the downlink data transfer and theuplink data transfer 306 are five (5) consecutive unused USFs 308-316(that is to say, USFs where the corresponding uplink allocation was notused to send user data) that extend within a given time duration 318. Inthis example, the time period since the most recent uplink or downlinkdata transfer or the number of unused USFs 308-316 may serve as theusage metric. In this case, the expiration of a predetermined durationor a period in which a predetermined number of consecutive USFs areunused and no downlink transfer occurs, whichever happens earlier, mayserve as a trigger for a timeslot monitoring reduction. For example, thepredetermined time period may be a period of 1 second and thepredetermined number of consecutive USFs may be 5. Thus, in the examplein FIG. 3, a timeslot reduction is triggered by unused USF 316 becausethe time period 318 since the most recent data transfer had yet toexceed the predetermined threshold.

However, turning to FIG. 4, as illustrated, the trigger may be caused bythe time period 318 (during which no data transfer occurred) exceedingthe predetermined threshold. Only four unused USFs 308-314 had occurredbefore the predetermined time period elapsed and, as described in thisexample, the threshold for unused USFs was 5.

Referring now to FIG. 5, another example for raising and utilizing atrigger is illustrated where reductions in timeslot monitoring for thedownlink channel 300 and the uplink channel 302 may occur independently.In this case, only two (2) unused USFs occur and an uplink data transfer320 occurs with a break in uplink transfer having a duration less thanthe predetermined time period. However, with respect to the downlinkchannel 300, the predetermined time period elapses without a downlinkdata transfer. As a result, the timeslot reduction procedure may beapplied independently to the downlink channel 300 while the uplinkchannel 302 continues in standard, or non-reduced timeslot monitoring.Thus, the timeslots to be monitored for downlink data may be reducedindependently of the amount of uplink data being sent, provided that thedownlink timeslots that need to be monitored for USFs allocating uplinkdata transfer are maintained, and vice versa.

Referring now to FIG. 6, another example for raising and utilizing atrigger is illustrated, this time in a downlink dual carrier assignment.As illustrated, in addition to the first downlink channel 300 and uplinkchannel 302, a second downlink channel 300′ and uplink channel 302′ areused. In this case, multiple downlink data transmissions may occursimultaneously, such as downlink data transmission 304 and downlink datatransmission 304′, on each downlink channel 300, and 300′. The reductionin timeslot monitoring may apply to each downlink channel 300, and 300′.In this example, there is no uplink assignment on uplink channel 302′,and, because there are no unused USFs, the trigger for downlink channel300′ determined by the predetermined time period elapsing is triggeredand timeslot monitoring reduction may take place. In this example,timeslot reduction applies independently to the two pairs of carriers(300 and 302) and (300′ and 302′). Therefore, with respect to downlinkchannel 300 and uplink channel 302, no timeslot monitoring reduction istriggered because a subsequent downlink communication 322 is sent andtwo uplink data communications 324, 326 are sent, thereby avoiding atrigger based on a predetermined time period between communicationselapsing or consecutive unused USFs.

Although a trigger may be based on the lack of uplink activity alone,such a trigger may result in inefficient system operation. Asillustrated in FIG. 7, the timeslots to be monitored for USFs arereduced as a result of multiple unused USFs 308-316. Due to thecommonality of timeslots used for USF monitoring and downlink datatransfer 304, however, the reduction in USF timeslots may not savesubstantial battery power because some or all of these timeslots willstill be decoded to receive the downlink data 304. Furthermore, if thedownlink data transfer 304 triggers an upper-layer request to transmituplink data, there could be a delay or poorer uplink bandwidth as thenumber of timeslots which can be allocated in the uplink is reduced.Referring to FIG. 8 and continuing with the example from FIG. 7, if thedownlink transfer 304 is followed by a pause in data transmission,while, for example, the user reads/watches the downloaded information,then the triggers as shown in FIGS. 3 & 4 would occur anyway in the caseillustrated in FIG. 8. That is, either the predetermined time period 318would elapse or the trigger would be raised due to continuing unusedUSFs 330-340. Because of the expected commonality of timeslots, theadditional benefit of the trigger shown in FIG. 7 (the difference inbattery consumption) compared with the case in FIG. 8 (for example,without that trigger) may be negligible.

Depending upon the system implementation, one or more triggers may bespecified, corresponding to a specific stage of the timeslot reductionalgorithm. The same number of triggers may be defined for both thenetwork and the UE, with each trigger corresponding to a stage in thealgorithm.

In one implementation, the triggers are different for network 104/BS 120and UE 102 of FIG. 1, with the network triggers occurring (in normaloperation in good radio conditions) earlier than those on the UE 102side. This allows for the possibility that a trigger occurs as USFs orother downlink data are being transferred between the BSC or schedulerof network 104/BS 120 and UE 102, or in case that one or more USFs ordownlink data blocks were not successfully received or decoded by the UE102, and ensures that network 104 or BS 120 is conservative in whichtimeslots it assumes UE 102 is monitoring. For example, if a triggerdefining a period of 1 second, or 5 unused uplink resource allocations(URAs) is defined for network 104, a corresponding trigger for the UE102 may be that no data is sent in either direction for 1.5 seconds, orthe UE 102 has not responded to 8 URAs, whichever occurs sooner.

To avoid timeslot reduction causing problems with acknowledgement ofcontrol blocks (including assignments), the system may define a minimumperiod since the last assignment message before any trigger can occur.Assignment messages may include messages which modify, add or reduce theset of resources assigned to UE 102. Examples are PACKET TIMESLOTRECONFIGURE messages, PACKET UPLINK ASSIGNMENT messages, HANDOVERCOMMAND messages, and the like. In one implementation, any time periodsor inactivity detection as specified by the trigger definition may notstart until some specified time period after the last assignment. Here,‘assignment’ may include assignment due to handover.

In the case that an assignment message (for example, assigning new, ordifferent resources) is sent to the UE, the overall timeslot reductionprocedure may either restart completely, with all timeslots that arepart of the new assignment being monitored, or may continue. In oneimplementation, an assignment message resulting in an increase inresources leads to the timeslot reduction procedure being restarted,while an assignment message which results in a decrease in resourcesleads to the procedure continuing. In the latter case, the timeslotreduction algorithm specifies which timeslots are to be monitored sothat if the timeslots which were being monitored prior to the newassignment are not part of the new assignment, new timeslots to bemonitored can be defined. If, in a downlink dual carrier assignment, anew assignment message which modifies assigned resources on only onechannel is received, the timeslot reduction algorithm may continue onthe second channel, independently.

In some applications, it is beneficial to allow the trigger algorithm(including any ongoing reduction in monitored timeslots) to continueafter an assignment message is received (as illustrated by FIG. 9 anddescribed below), such as when the assignment message reduces the totalamount of resources assigned to the UE. This may operate to avoidsimultaneous attempts to reduce the number of monitored timeslots byboth reducing the assignment, and by means of the timeslot reductionalgorithm whereby, otherwise, the number of monitored timeslots mayactually increase as a result of the assignment message.

Referring to FIG. 9, a dual downlink and uplink channel system isillustrated receiving an assignment message after timeslot reduction istriggered. The downlink channel 300, uplink channel 302, second downlinkchannel 300′ and uplink channel 302′ are used. Using the system,multiple downlink data transmissions may occur simultaneously, such asthe downlink data transmission 304 and downlink data transmission 304′,on each downlink channel 300, and 300′. Alternatively, data transfer mayoccur independently on a single channel, as indicated by the downlinkdata transmission 342. Similarly, data uplink transmissions, such as thedata transmission 344, may occur simultaneously, quasi-simultaneously,or independently, as required by various specifications or systemrequirements. As shown on FIG. 9, a trigger occurs on the downlinkchannel 300′ due to the expiration of a predetermined time period 346initiating timeslot monitoring reduction. After timeslot monitoringreduction is triggered, an assignment message 348 is issued to the UE102. This assignment message 348 may grant to the UE increased ordecreased resources. If the assignment message 348 further reduces thetimeslot assignment for downlink channel 300′, as indicated in FIG. 9,timeslot reduction on downlink channel 300′ is continued, even afterdownlink channel 300′ receives assignment message 348. On the otherhand, if an assignment message is received that increases the resourcesfor this UE, reduced timeslot monitoring may be discontinued unlessanother trigger re-initiates reduced timeslot monitoring. In othercases, it may be desirable to continue with reduced timeslot monitoringdespite receiving an assignment message granting increased resources.

Upon detection of a trigger event, timeslot reduction is initiated.Generally, timeslot reduction allows the UE 102 to reduce the number ofdownlink timeslots which it monitors in an effort to control energyexpenditure and attempt to maximize battery life. With reference tonetwork 104, a trigger reduces the range of timeslots during which thenetwork 104 can transmit USFs, downlink data, or other controlinformation to the UE 102. Depending upon the system implementation, noadditional explicit signaling is used after the trigger event occurs toinitiate the timeslot monitoring reduction.

In some implementations, however, the UE 102 and network 104 maycommunicate certain confirmation or synchronization messages to ensureboth UE 102 and network 104 are participating in the same, or equivalenttimeslot reduction activities. For example, although it may not bepreferable for explicit signaling from the network 104 to UE 102 toindicate the timeslot reduction, the UE 102 may affirm to network 104which timeslots it is monitoring. In one implementation, the UE 102notifies the network 104 by responding to a poll request or USF with acontrol block indicating its current status. This may be doneperiodically or by responding using the first available uplinkallocation after each trigger to indicate that the trigger has occurred.Although adding communication overhead, this process may reduce thepossibility that the network 104 expects the UE 102 to be monitoringtimeslots which the UE 102 is not monitoring. In one implementation, theindication from the UE 102 could be an existing dummy block if the UE102 is not normally required to send dummy blocks when it has no otherdata to send.

Each trigger may be associated with a specific timeslot reductionalgorithm for determining the process by which the reduction in timeslotmonitoring takes place after a trigger is detected. For example, thereduced set of timeslots may be determined by means of an algorithmknown in advance to both the UE 102 and network 104 (although UE 102 andnetwork 104 may be configured to implement different triggeralgorithms). Which timeslot reduction algorithm to implement may beidentified as part of the TBF establishment/modification processes orother communication process between the UE 102 and network 104, or maybe identified by means of some specified, deterministic algorithm or acombination of the two.

In one implementation the timeslot reduction algorithm takes intoaccount timeslots which (according to the current assignment) may bemonitored both for USFs and downlink data and reduces the requirement tomonitor other timeslots that are used only for USFs or only for downlinkdata. Depending upon the timeslot reduction algorithm, at a point ofmaximum reduction of timeslot monitoring, no more than 1 timeslot (or inthe case of reduced transmission time interval (RTTI) downlink or RTTIUSF mode, no more than two timeslots) may be monitored in any TDMAframe, and is used both for downlink data and for USF signaling.Depending upon the system implementation, multiple triggers may occursequentially, each leading to a further reduction in timeslotmonitoring.

Various timeslot reduction algorithms may be implemented by each of theUE 102 and network 104 in response to either the UE 102 or network 104detecting a trigger. For example, a timeslot reduction algorithm maycontain 1 or more stages, with each stage corresponding to a trigger.The timeslot reduction algorithm may be implemented by a reduction tothose timeslots whose number is common to both uplink and downlinkassignments (for example, those timeslots that may be monitored both forUSFs and for downlink data), a reduction by a fixed number of timeslots,such as decreasing from either the “left” or “right” (i.e., removingthose with the lowest or highest, respectively timeslot numbers first),a reduction by a fixed proportion of timeslots, or a reduction so thatin some radio block periods, no timeslots are monitored by the UE 102(or used by the network to send USFs or downlink data), for example touse/monitor timeslots only in alternate radio block periods. Thisapproach is beneficial in RTTI with USF mode, because RTTI USF moderequires monitoring at least 2 USFs per TDMA frame, and this approachcould allow the reduction to the equivalent of 1 USF per TDMA frame onaverage. Alternatively, the timeslot reduction algorithm may include areduction to no less than 1 timeslot for uplink allocation and 1timeslot for downlink data (which may be the same) or in downlink dualcarrier implementations, a reduction by removal of all timeslots onchannel 2 (or on channel 1, if channel 1 has no uplink resourcesassigned and channel 2 does). Generally, the timeslot reductionalgorithm stages are defined so that they are deterministic, and basedupon the current radio resource assignment.

The timeslot reduction algorithm may be configured to removelow-numbered timeslots initially. This may be advantageous in casesinvolving systems implementing EDA, for example, where EDA continues tooperate when timeslot reduction is in use (e.g., less than the completeassignment is being monitored by the UE 102) and the UE 102 may not havereduced its timeslots by the same amount as that expected by the network104, and may otherwise consider that a USF allocates more uplinkresources than is the intention of the network 104. Depending upon thesystem implementation, the expectation may be that the use of EDA issuspended during timeslot reduction (known both to the UE and thenetwork) or the expectation may be that the use of EDA continues duringtimeslot reduction.

Alternatively, the network 104 could assign to each UE one or moretimeslots that are to be monitored in the event of timeslot reduction,to allow distribution of monitoring for different UEs 102 which shareassigned timeslots and to avoid the possibility that multiple UEs 102 ina reduced monitoring state are monitoring the same timeslot.

In some implementations, the determination of whether EDA is to be usedby UEs 102 in a reduced monitoring state may be signaled by the network104, for example, by means of an assignment message. Because EDA canallow the allocation of a large amount of uplink resources by means of asingle USF, it may be advantageous to disable EDA for UEs in a reducedmonitoring state if the network is heavily congested and such largeresource allocation (which may be wasted if the UE 102 has no data tosend) would deprive other UEs of uplink resources.

Triggers and any associated timeslot reduction algorithms may be definedindependently for uplink data and downlink data (for example, so thatafter a sustained period where no uplink data is sent, the timeslots tobe monitored for USFs are reduced, but no change is made to themonitoring for downlink data) or, jointly (for example, after asustained period where no uplink or downlink data has been sent,timeslots to be monitored for both USF and downlink data are reduced).In the case of a downlink dual carrier assignment, triggers andalgorithms may operate jointly over both pairs of channels (with eachpair comprising one uplink channel and one downlink channel), or mayoperate independently on each pair of channels.

Timeslot monitoring reduction may be specified to occur (in the absenceof loss of data/decoding errors) simultaneously (allowing forpropagation delays, transmission time and decoding delays) at both theUE 102 and network 104. In one implementation, however, the reduction intimeslot monitoring occurs at the network 104 side first. This approachensures that the network 104 is conservative and will not overestimatethe timeslots being monitored by the UE 102. For example, in the case ofpoor radio conditions and/or decoding errors by the UE 102, it isimportant that the network 104 not anticipate that the UE 102 ismonitoring particular timeslots after a trigger has cause the UE 102 toignore those timeslots.

In some circumstances, the UE 102 may determine that it is necessary todelay any decrease in the number of timeslots being monitored. Forexample, if a user is taking an action using the UE 102 that will resultin later network activity (such as preparing an email, or filling out aweb-based form), the UE 102 may instruct the network 104 to delay anytimeslot monitoring reduction to ensure optimal performance when networkcommunications are ultimately initiated. In one example, to delay adecrease in the number of timeslots being monitored, the UE 102 mayrespond proactively to a USF either by means of an existing dummy blockformat, a specified block format or other predetermined communication,even though it does not currently have data to send, to delay a trigger(and hence the reduction of timeslots being monitored). If the UE 102 isaware that it will imminently have data to send or receive, for examplebecause the UE 102 monitors user activity and anticipates a future datatransmission need, the UE 102 may elect to delay any reduction intimeslots monitored to allow a higher bandwidth transmission to startsooner.

Depending upon the system implementation, the UE 102 may delay areduction in timeslot monitoring by undertaking any action indicatingthe UE 102 wishes to delay the reduction. For example, if the network104 normally does not require any response to a USF, the UE 102 maydelay the timeslot reduction by sending a response. If the networknormally does require a dummy response to a USF, then the UE 102 maydelay the timeslot reduction by sending a new version of the dummyresponse.

In contrast, the UE 102 may wish to initiate timeslot monitoringreduction prematurely. If so timeslot reduction may be initiated, forexample, by the UE 102 failing to send an anticipated dummy block. Thismay be useful if the UE 102 determines it has a low battery level, orknows that no transmission is likely to occur.

The method steps 200 illustrated with respect to FIG. 2, may beimplemented in a system employing EDA, wherein a reduced set oftimeslots is being monitored for communications or other data such as aUSF. As previously discussed, depending upon the implementation, EDA mayor may not apply when timeslot reduction as implemented by method steps200 is active. In the first case, where EDA applies when timeslotreduction is active, UE 102 monitors for USF on the reduced timeslot(s)as per the reduction algorithm. In one example, illustrated in FIG. 10,the downlink channel 300 and uplink channel 302 implement EDA. A reducedtimeslot number set is defined as timeslot 2 in the downlink channel 300and the original uplink assignment is for timeslots 2, 3, and 4. In thatcase, the UE 102 monitors timeslot 2 for a USF 350 transmitted via thedownlink channel 300. If the UE 102 detects the USF 350 for itself onthe reduced set of timeslots (in timeslot 2 in the example), then itwill transmit via the uplink channel 302 on all of its assigned uplinktimeslots 352, 354, and 356 that have the same or higher timeslot numberthan the downlink timeslot on which the USF was received (timeslots 2,3, and 4 in this example).

Conversely, in the second case where EDA does not apply when timeslotreduction is active, the UE 102 monitors for a USF on the reducedtimeslot(s) as per the reduction algorithm (timeslot 2 in this example),and if the UE 102 sees a USF for itself on this reduced set of timeslots(timeslot 2 in this example), then it will transmit on the uplink onlyon the TS where the downlink USF was received (timeslot 2 in thisexample).

Although the use of EDA in the above manner may result in efficienttransmission of a given amount of data using multiple blocks sent in thesame radio block period, the allocation of multiple radio blocks bymeans of EDA which are subsequently unused (because the UE has no datato send) is inefficient from a system capacity point of view. Forexample, if the network 104 knows that the UE 102 is using EDA, then, ifit sends the UE 102 a USF in slot “n”, it needs to reserve slot “n” andall of the uplink timeslots that are assigned to that UE 102 that arehigher than “n”, and cannot assign them to any other user.

In one implementation of the present system, where EDA is active, thetimeslots to be monitored may vary over time, for example, radio blockperiod by radio block period, so that if only one timeslot is monitoredin any given radio block period, it is not the same timeslot number inall radio block periods. This gives the network 104 more freedom inallocating uplink resources to the UE 102 to balance the tradeoffbetween efficient data transmissions from the UE 102 because it can senddata in multiple timeslots having only had to receive a single USF, andreduced efficiency in overall management of the network 104 when thenetwork 104 reserves those uplink timeslots for UE 102 and the UE 102does not use them. In this implementation, in the timeslot reductionalgorithm having EDA enabled, the network 104 and UE 102 know to varythe timeslot during which the USF is sent/monitored. This may changeperiodically, possibly in each radio block period, which allows the UE102 opportunities to transmit in more than one uplink slot per radioblock period, while reducing the penalty to the network 104 by nothaving this situation every radio block period.

For example, as illustrated in FIG. 11, the downlink channel 300 anduplink channel 302 implement EDA, while allowing monitored timeslots tovary over time. As illustrated, the UE 102 receives an initial uplinkassignment for timeslots 2, 3 and 4. In this case, timeslot monitoringreduction is used with EDA enabled. In radio block period RBP1, thenetwork 104 transmits a USF 358 via the downlink channel 300 to the UE102 in timeslot number 2. If the UE 102 has data to send, it may send itin any or all of timeslots 2, 3, and 4 (indicated by elements 360, 362and 364 on FIG. 11) in the next radio block period, RBP2. Thus, thenetwork 104 reserves these timeslots for this UE 102 within uplinkchannel 302 (without knowing whether or not they will be used) andcannot allocate them to any other UE for this radio block period.

In the next radio block period, RBP3, the network 104 transmits a USF366 for the UE 102 via the downlink channel 300 in timeslot number 3. Ifthe UE 102 has data to send, it may send it in timeslots 3 and 4(indicated by elements 368 and 370 on FIG. 11) in the next radio blockperiod, RBP4. As such, the network reserves these two timeslots for thisUE 102 on the uplink channel 302 (again it doesn't know if they will beused or not) and does not allocate them to any other UE for this radioblock period.

In the next radio block period, RBP5, the network 104 transmits a USF372 for the UE 102 via the downlink channel 300 in timeslot number 4. Ifthe UE 102 has data to send, it may only send it in timeslot 4(indicated by element 374 on FIG. 11) in the next radio block period,RBP6. Accordingly, the network reserves one timeslot in the uplinkchannel 302 for the UE 102. This case is the most efficient for network104 and is the least efficient for the UE 102, if the UE 102 hasmultiple data blocks to send.

In the next radio block periods, this pattern repeats and the network104 again transmits the USF for the UE 102 in timeslot number 2. The UE102 and network 104 know the repeating pattern of where to send/monitorfor the USF as it is either part of the defined timeslot reductionalgorithm, explicitly signaled, or otherwise communicated between the UE102 and network 104. For example, if the timeslot or timeslots beingmonitored for each USF changes in each radio block period (e.g., asdescribed above), the network will also change its downlink slotaccording to the same algorithm so that the timeslots for data/uplinkUSF monitoring stay the same. In this example, the network 104 allocatesresources by means of USFs sent in each of the radio block periods RBP1,RBP3, and RBP5; alternatively the network 104 may allocate resources inonly a subset of radio block periods, taking into account, for example,the demand for uplink allocations from other mobile stations and/or thebenefit of allowing the UE 102 to send multiple uplink radio blocks bymeans of a single USF. Note that the sending of any USFs are undercontrol of network 104. In the example above the network 104 may choosenot to signal one or more of USFs 358, 366, or 372.

Turning now to FIG. 12, an implementation of the method steps 200 ofFIG. 2 are illustrated, where RTTI is used in the downlink and/or whereRTTI USF mode is used to allocate uplink resources where the timeslotreduction algorithm specifies not only on which timeslot numbers tomonitor the downlink, but also in which radio block periods (forexample, to monitor during only every other radio block period). Thisallows a further reduction in monitoring requirements below thoserequired to detect one USF/downlink radio block per radio block period.As shown in FIG. 12, the network 104 sends via the downlink channel 300a USF over 2 timeslots 376 and 378 in a reduced radio block period of 10ms, indicated by RRBP1. In this case, timeslot reduction can be reducedto no fewer than 2 timeslots to support the USF; however, the UE 102only needs to monitor every other reduced radio block period for theUSF. If the UE 102 has data to send, it may transmit via the uplinkchannel 302 in timeslots 2 and 3, indicated by elements 380 and 382 inFIG. 12. The UE 102 is not required to monitor any timeslots in RRBP2.In the next reduced radio block period, RRBP3, a USF is sent viadownlink channel 300 over 2 timeslots 384 and 386 in a reduced radioblock period of 10 ms, indicated by RRBP3. In this case, timeslotmonitoring can be reduced to no fewer than 2 timeslots to support theUSF; however, the UE 102 only needs to monitor every other reduced radioblock period for the USF. If the UE 102 has data to send, it maytransmit via uplink channel 302 in timeslots 2 and 3 in the next reducedradio block period, indicated by elements 388 and 390. In oneimplementation, downlink channel 300 uses the same timeslots for datatransmission as are monitored by the UE 102 for uplink USFs. In thisexample the network 104 allocates resources in each of the radio blockperiods during which the UE 102 monitors downlink timeslots;alternatively the network may allocate resources in only a subset ofsuch radio block periods. Note that the sending of any USFs are undercontrol of network 104. In the example above the network 104 may choosenot to signal one or more of USFs sent on timeslots 376, 378, 384, and386.

FIG. 13 illustrates one example data flow sequence between a UE 402 anda network 404 when carrying out the steps of method 200 of FIG. 2 wheretrigger rules vary between the network 404 and UE 402. The first usagemetric for raising a trigger applies to the network 404. In particular,when the UE 402 has not responded to three consecutive USFs, thetimeslots which the network 104 considers to be being monitored by theUE 102 are to be reduced to 1 by removing low-numbered timeslots. Thesecond usage metric for raising a trigger applies to the UE 402. Inparticular, when UE 402 has not responded to 4 USFs, the UE 402 reducesthe monitored timeslots to 1 by removing low-numbered timeslots. In thisimplementation of the trigger algorithms, there is only a singletrigger, as no further reduction of monitored timeslots can occur. Also,it is assumed that timeslot 6 is part of both the uplink and downlinkassignments.

As illustrated in FIG. 13, at time t=0, the UE 402 is monitoringtimeslots 4, 5, and 6 and this monitoring configuration is also known tothe network 104 (see boxes 403, and 405, respectively). As the network404 and UE 402 operate they communicate data back and forth. As shown onFIG. 13, the network 404 transmits user data 406 and then a USF 408 tothe UE 402. After receiving the USF 408, the UE 402 transmits user data410 to the network 404. At this point, the UE 402 is monitoringtimeslots 4, 5, and 6. The network 404 then transmits USFs 412, 414, and416 to the UE 402, with no responsive data being communicated from theUE 402 to network 404. After receiving no response to USFs 412, 414, and416, the network 404 detects that a trigger event has occurred (i.e.,three successive USFs, with no response from the UE 402) and reduces theset of timeslots which it expects the UE 402 to be monitoring inaccordance with the trigger. With reference to FIG. 13, at this pointthe network 404 expects the UE 402 to monitors only timeslot 6 (see box405′). The network 404 again issues a USF 418, but only via timeslot 6.At this point, the UE 402 is monitoring timeslots 4, 5, and 6 andreceives the USF 428. After receiving USFs 412, 414, 416, and 418,however, and having no responsive data, the UE 402 determines that itsown trigger event has occurred (4 successive USFs) and begins monitoringonly timeslot 6 (see box 403′).

FIG. 14 illustrates another example data flow sequence between the UE402 and network 404 when carrying out the steps of method 200 of FIG. 2,when there is a lack of synchronization of triggers (in this case causedby the UE 402 not detecting a USF). As will be described, unliketraditional systems and methods that rely heavily on tight coordinationand synchronization between the UE and network, the present disclosureis able to readily handle such a lack of synchronization between the UE402 and network 404. In one configuration, a lack of synchronizationdoes not generate difficulties because the timeslots that the network404 believes the UE 402 to be monitoring are a subset of those that theUE is actually monitoring. As shown in FIG. 14, the network 404transmits user data 420 and then a USF 422 to the UE 402. Afterreceiving the USF 422, the UE 402 transmits user data 424 to the network404. At this point, the UE 402 is monitoring timeslots 4, 5, and 6 andthe network 404 expects the UE 402 to be monitoring timeslots 4, 5, and6 (see boxes 403 and 405, respectively). The network 404 then transmitsUSFs 426, 428, and 430 to the UE 402, with no responsive data beingcommunicated from the UE 402 to the network 404. After receiving noresponse to USFs 426, 428, and 430, the network 404 detects that atrigger event has occurred (three successive USFs with no response fromUE 402) and reduces the set of timeslots it believes the UE 402 to bemonitoring in accordance with the trigger. At this point, the network404 expects the UE 402 to only monitor timeslot 6 (see box 405′). Inthis example, however, the UE 402 did not receive USF 430, and, as aresult, only counts two unused USFs transmitted by network 404. Afterreducing the timeslots the network 404 believes the UE 402 to bemonitoring, the network 404 transmits USFs 432 and 434, but only viatimeslot 6. At this point, the UE 402 is still monitoring timeslots 4,5, and 6 (it did not detect USF 430), so still receives USFs 432 and434. However, after receiving USFs 426, 428, 432, and 434 (the UE 402did not detect or otherwise receive USF 430) and having no responsivedata, the UE 402 determines that its own trigger event has occurred (4successive unused USFs) and begins monitoring only timeslot 6 (see box403′).

FIG. 15 illustrates another example data flow sequence between a UE 402and a network 404 when carrying out the steps of method 200 of FIG. 2when operating in an RTTI configuration and where the reduction intimeslots distinguishes between odd and even radio block periods. Thefirst usage metric for raising a trigger applies to the network 404 andstates that when the UE 402 has not responded to 3 USFs, the network 404will only expect the UE 402 to monitor timeslots in even RTTI radioblock periods. The second usage metric for raising a trigger applies tothe UE 402 and states that when the UE 402 has not responded to 4 USFs,the UE 402 will reduce monitored timeslots to an average of 1 per TDMAframe (counting only TDMA frames which can be used for data transfer) byonly monitoring timeslots in even radio block periods. As illustrated inFIG. 15, at time t=0, the UE 402 is monitoring timeslots 4, and 5 inboth even and odd radio block periods and the network 404 expects the UE402 to be monitoring timeslots 4, and 5 in both even and odd radio blockperiods (see boxes 405, and 403, respectively). As the network 404 andUE 402 operate, they communicate data back and forth. As shown on FIG.15, the network 404 transmits user data 436 and then USF 438 to the UE402. After receiving the USF 438, the UE 402 transmits user data 440 tothe network 404. The network 404 then transmits USFs 442, 444, and 446to the UE 402, with no responsive data being communicated from the UE402 to the network 404. After receiving no response to USFs 442, 444,and 446, the network 404 detects that a trigger event has occurred(three successive USFs, with no response from UE 402) and stopsexpecting the UE 402 to monitor timeslots on odd radio block periods inaccordance with the trigger. At this point, the network 404 expects theUE 402 to only monitor timeslots 4 and 5 during even radio block periods(see box 405′). The network 404 again issues a USF 448, but only viatimeslots 4 and 5 during the even radio block periods. At this point,the UE 402 is monitoring timeslots 4 and 5 in both even and odd radioblock periods, so still receives the USF 448. After receiving USFs 442,444, 446, and 448, however, and having no responsive data, the UE 402determines that its own trigger event has occurred (4 successive USFswith no responsive data) and begins monitoring timeslot 4 and 5 only ineven radio block periods (see box 403′).

The present system and method allows for USFs to be robustly encoded. Asa result, a lack of response (or a response consisting of dummy blocks)is robust to detect. Using method 200, additional signaling is reduced(although additional optional messages may be included to modify ordefine assignments, to enable or disable particular features, toindicate subset of timeslots to be applied, or to indicate triggerparameters or specifications). The steps of the method 200 describedwith respect to FIG. 2 may be implemented by the UE which has awarenessof application-level status improving the accuracy over a method wherebythe network or BSC estimates future data transmissions.

Referring again to FIG. 1, having provided for the reduction of timeslotmonitoring to improve an efficiency of communications between the UE 102and network 104, the present disclosure allows for the inverseprocess—an increase in timeslot monitoring. An increase in timeslotmonitoring allows the UE 102 and network 104 to resume improved networkperformance during active data communication. The system may increasethe number of monitored timeslots in response to particular user datatransmitted by either the UE 102 or network 104, or any other messagetransmitted by either the network 104 or UE 102. Both the UE 102 andnetwork 104 may increase the number of timeslot monitoring in a reverseapplication of the timeslot reduction algorithm defined above. Forexample, in a downlink dual carrier assignment, data sent on one channelmay result in all timeslots on only that channel being monitored, or mayresult in all timeslots (on both channels) being monitored.Alternatively, upon receiving a predetermined transmission indicating aresumption of timeslot monitoring, both the UE 102 and network 104 maysimply resume the monitoring of all assigned timeslots. In otherimplementations, other algorithms may be applied to determine the speedand progression with which both the UE 102 and network 104 resumemonitoring particular assigned timeslots.

The indication to resume monitoring of particular assigned timeslots maybe made by the UE 102 responding to a USF when timeslot reduction isactive either by means of an existing dummy block format, or by means ofanother specified block format. This allows the UE 102 to increasetimeslot monitoring by the network 104 if the UE 102 does not currentlyhave data to send, but is aware or expects that it will imminently havedata to send or receive. By allowing the UE 102 to increase timeslotmonitoring, a higher bandwidth transmission of data between the UE 102and network 104 can start sooner, and with improved bandwidth. As willbe appreciated by one of skill in the art, the UE 102 may use the sameor substantially similar process to that of increasing timeslotmonitoring to delay decreased timeslot monitoring. That is, for example,the UE 102 may monitor expected or anticipated communications with thenetwork 104 and, upon identifying a trigger for the UE 102 and/or thenetwork 104 that would cause a reduction in timeslot monitoring, maycommunicate a dummy block or other specified block format to delay theimpending reduction in timeslot monitoring. Once again, this is anillustration of a break from traditional paradigms where the network 104dictates to the UE 102.

In one implementation, the UE 102 increases the number of timeslots itmonitors within a timeframe that is shorter than that for reacting tonew assignment messages. A maximum value for this shorter reaction timeis known to both the network 104 and UE 102, so that the network 104knows when the UE 102 is monitoring an increased set of timeslots. Forexample, an increase in the number of monitored timeslots (which may beup to the full assignment of timeslots as used before the initiation ofthe timeslot reduction algorithm) may occur within a predeterminednumber of radio block periods after certain information or data blocks,or other transmissions have been sent or received in either direction(or in the specific direction, if the algorithm is operatedindependently in each direction) between the UE 102 and network 104. Theinformation may be any combination of user data, control messages, pollsfor control information, or specific contents thereof and may be knownto both the UE 102 and network 104. It is not necessary that theinformation be signaled during application of the algorithm. In oneimplementation, however, the predetermined information to initiate anincrease in monitored timeslots is signaled as part of an assignmentmessage sent to the UE 102.

If the network 104 is transmitting data to UE 102, the data may beacknowledged before the complete full assignment is used. In that case,however, the network 104 may preemptively transmit on the fullassignment of timeslots before an acknowledgement has been received.Alternatively, it may be sufficient that the UE 102 or network 104detects the data and can decode it sufficiently to identify that userdata has been sent (compared with dummy blocks, for example, if theseare to be transmitted by the UE in response to USFs)—it may not berequired that the receiver is able to decode the entire data correctly.

While several embodiments have been provided in the present disclosure,it should be understood that the disclosed systems and methods may beembodied in many other specific forms without departing from the spiritor scope of the present disclosure. The present examples are to beconsidered as illustrative and not restrictive, and the intention is notto be limited to the details given herein. For example, the variouselements or components may be combined or integrated in another systemor certain features may be omitted, or not implemented.

Also, techniques, systems, subsystems and methods described andillustrated in the various embodiments as discrete or separate may becombined or integrated with other systems, modules, techniques, ormethods without departing from the scope of the present disclosure.Other items shown or discussed as coupled or directly coupled orcommunicating with each other may be indirectly coupled or communicatingthrough some interface, device, or intermediate component, whetherelectrically, mechanically, or otherwise. Other examples of changes,substitutions, and alterations are ascertainable by one skilled in theart and could be made without departing from the spirit and scopedisclosed herein.

1. A method for coordinating communications between a user equipment anda base station, comprising: receiving an assignment of a first set oftimeslots for at least one of uplink and downlink communications betweenthe user equipment and the base station; and transmitting to the basestation an instruction to delay a reduction of a number of timeslotsmonitored by the user equipment to less than the first set of timeslotsfor communications.
 2. The method of claim 1, wherein the instructioncomprises at least one of a predetermined communication and a blockincluding at least one of a dummy block format and a specified blockformat.
 3. The method of claim 1, wherein the instruction comprises apacket uplink dummy control block.
 4. The method of claim 1, includingtransmitting a control block to the base station, the control blockidentifying one or more timeslots being monitored by the user equipment.5. The method of claim 1, wherein receiving an assignment of a first setof timeslots includes receiving an assignment message from the basestation.
 6. The method of claim 1, including transmitting theinstruction to the base station after at least one of uplinkcommunications and downlink communications reaches a usage metric. 7.The method of claim 6, wherein the usage metric is received at least oneof in an assignment message and via packet data protocol (PDP) contextestablishment procedures.
 8. A method for coordinating communicationsbetween a user equipment and a base station, comprising: transmitting anassignment of a first set of timeslots for at least one of uplink anddownlink communications between the user equipment and the base station;and receiving an instruction from the user equipment, the instructiondelaying a reduction in a number of timeslots monitored by the userequipment to less than the first set of timeslots for communications. 9.The method of claim 8, wherein the instruction comprises at least one ofa predetermined communication and a block including at least one of adummy block format and a specified block format.
 10. The method of claim8, wherein the instruction includes a packet uplink dummy control block.11. The method of claim 8, including receiving a control block from theuser equipment identifying one or more timeslots being monitored by theuser equipment.
 12. The method of claim 8, wherein transmitting anassignment of a first set of timeslots includes transmitting anassignment message to the user equipment.
 13. The method of claim 8,including receiving the instruction after at least one of uplinkcommunications and downlink communications reaches a usage metric. 14.The method of claim 13, wherein the usage metric is transmitted at leastone of in an assignment message and via packet data protocol (PDP)context establishment procedures.
 15. A user equipment for use with acommunications network including a base station, comprising: a processorconfigured to: receive an assignment of a first set of timeslots for atleast one of uplink and downlink communications between the userequipment and the base station; and transmit to the base station aninstruction to delay a reduction of a number of timeslots monitored bythe user equipment to less than the first set of timeslots forcommunications.
 16. A base station for use with a communications networkincluding a user equipment, comprising: a processor configured to:transmit an assignment of a first set of timeslots for at least one ofuplink and downlink communications between the user equipment and thebase station; and receive an instruction from the user equipment, theinstruction delaying a reduction in a number of timeslots monitored bythe user equipment to less than the first set of timeslots forcommunications.